Diagnosis of Stones
Intravenous Pyelogram (IVP) and Tomography
Pyelogram (IVP), also referred to as intravenous urogram (IVU) or
EXcretory Urography (EXU) has been the modality of choice for radiographic
evaluation of patients with suspected urinary calculi. IVP can verify
the presence of a calcification on a plain radiography that is within
the ureter and also delineates the anatomical relationship of the
urinary tract to the calcification. The collection of contrast within
the urinary tract is able to identify the presence of a urinary
tract stone and the presence or absence of obstruction. Obstruction
by the stone or calcification is evident by delayed opacification
of the affected kidney and collecting system while the normal kidney
(opposite or contralateral kidney) already has relatively reduced
opacification by the excretion of contrast from the kidney.
IVP. Ten-minute excretory urogram shows normal kidneys, ureters
and contrast filling of the bladder.
film tomography is utilized to increase the recognition of renal
masses, fine renal calcifications and paranephric structures. The
tomograms should be obtained just before or just after the 3-minute
films, usually 8cm to 10cm from the posterior abdominal wall (or
table top) to ensure a satisfactory nephrogram and early calyceal
kidneys. Tomogram demonstrates the presence of the right and
left kidney (yellow arrowheads).
Identifying the anatomical relationship of the urinary tract system
to the calcification.
Demonstrate the presence for absence of urinary tract obstruction.
Good survey of the urinary tract system.
Can evaluate the contralateral kidney.
Missing small stones.
The passage of stones causing edema or swelling at the UVJ mimicking
the appearance of a retained stone.
Risks associated with intravenous contrast (adverse reactions
including anaphylaxis, pruritus and renal failure).
Exposure to ionizing radiation.
Quality of study may be limited by inadequate bowel preparation,
bowel ileus, swallowed air and technician variability.
Inconvenience of a long filming sequence.
If IVP is negative for obstruction calculus, it may fail to adequately
diagnosis other extraurinary causes of acute flank pain.
dye is injected into the patient's vein. The dye is collected within
the urinary tract system. This dye is visible on x-ray. A series
of x-rays are obtained before (scout film) and after contrast is
injected. The dye allows the physician to determine the location
of the stone, the presence of obstruction, the anatomy of the urinary
tract and whether the stone is radiolucent or radio-opaque.
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